Process for rendering textiles water-repellent



Patented Sept. 7, 1937 UNITED STATES PROCESS FOR RENDERING TEXTILES WATER-BEPELLENT Alexander Nathansohn, Berlin, Germany, as-

signor to the firm Studiengesellschaft fiir Faserveredelung m. b. H., Berlin, Germany No Drawing. Application June 25, 1935, Serial No. 28,356. In Germany July3, 1934 .4 Claims.

It has been proposed to render textiles repellent to water by impregnating them with emulsions of anhydrides of high molecular fatty acids, subsequently drying, and allowing the material to ripen at a raised temperature. In processes hitherto described, ammonia is preferably used as an emulsifying agent and to the emulsion so obtained a solution of starch or the like is generally added. The ripening is usually efiected at temperatures between 60 and 80 C. for 6 to 24 hours. These known processes'produced favor able results but, owing to the long ripening pe-' riod, which causes great-wear of the apparatus and renders continuous working quite impossible, the economic carrying out of the process is very difficult. Moreover the emulsions are not very stable since, if the stirring is discontinued, the fatty substance separates from the aqueous phase and it is therefore necessary to prepare the emulsions several times in course of one performance of the process.

The above mentioned disadvantages of the processes hitherto known can be avoided in a surprising manner if soap is used as an emulsifying agent. A suitable emulsion can for instance very easily be prepared if to the anhydride, if desired a molten anhydride of a high molecular fatty acid, that is to say, a fatty acid with more than 10 carbon atoms, there is added 50 times its quantity of a 0.75% soap solution at 75 (1, and the mixture is energetically stirred for a few minutes and subsequently diluted with the same quantity of warm water. The textile material to be treated is then immersed in 'such'an emulsion in a suitable apparatus, squeezed ofi, dried, and

exposed for a comparatively short time, for instance 15 to 60 minutes, to a temperature of about 80 C. The material is then rinsed until the odor of soap has been removed, and it is then again dried. It is thus rendered to a high degree repellentto water. The feel of the textile material has remained unchanged as compared with untreated material; further, the-water repellent efiect is not destroyed by ordinary washing. Y In the case of hosiery, knitted goods and woven material made of cotton which has not been bleached and not been kier-boiled and which may have been'dyed if desired, it has proved advantageous to usehigher temperatures for ripening, such as temperatures above 130 0., preferably a temperature of about 150 C., and to ripen -for a short time. It is'advisable to clean the material in the usual manner before it is treated for instance by washing with soap, saponine, synthetic washing agents, or the like,

Example 1.10 kilograms of a fatty acid anhydride, prepared by boiling commercial stearlne with an excess of acetic anhydride and subsequently distilling oil? the acetic anhydride and the acetic acid produced, are melted and 250 5 litres of a 0.75% solution of shredded potash soap are poured onto the molten fatty acid anhydride at 75 C. whereupon the mixture is stirred and subsequently diluted with 250 litres of hot water. White cotton twill is treated with this emulsion; 10 the material is then squeezed. oif, dried in the usual manner and treated at about 80 C. for hour; the soap is then removed by. rinsing, and the material is dried in the usual manner.

Example 2.Printed woven material made of 5 artificial silk is treated in. the same manner as described in Example 1.

Example 3.--Knitted fabric made of wool and staple fibres is treated as described in Example 1, but is exposed only for 15 minutes to a temperature of 80 C.

Example e f-Cotton goods made of cotton which'has not been bleached and not been kierboiled, are impregnated with an emulsion prepared according to Example 1, dried, exposed for 25 20 minutes to a temperature of about 150 0., and after this ripening process they are rinsed with water and again dried.

The process may be slightly simplified in some cases, particularly in case that the soap smell carried along with the goods after impregnating and drying is not inconvenient. In such cases rinsing of the soap is not necessary, and the process is finished when the goods have been impregnate'd and dried. Indeed it has been found that if soap and anhydrid remain within the textile goods the water repelling efiect gradually occurs, for instance after twenty-four hours, even if the goods are not longer exposed to an in- 40 creased temperature after drying. It will be understood that the soaps to be used with the said manner of carrying out the process should be as inodorous as possible. In such cases the use of so-called cold-stirred soaps, that is to say, soaps produced from alkali and fatty acids or fats without boiling, has turned out especially well, as the said soaps generally have no inconvenient smell and are stable at the temperature employed for ripening.

In other cases, however, in which especially clean goods are to be obtained, it may be suitable not only to rinse the goods as above described, but also toexpose them moreover to an especiallyintensive cleaning either with soap or with other cleansing means.

The process produces a remarkably strong effect and the short ripening period which, com pared with other methods of applying the anhydrides of high molecular fatty. acids, is one of its '5 principal advantages, is particularly surprising. In view of the conditions under which the process is carried out, it can hardly be assumed that an esteriflcation takes place; the efiect produced shows on the contrary an obvious connection with the phenomena of a process described by applicant for rendering wool repellent to water (cf. Ser. No. 752,532, filed November 10, 1934). In the case of wool the resistance to water can be obtained by using soap only; when other tex- 5 tiles are to be treated it is necessary to use the described combination of soap and anhydride. The analogy supports the assumption that in both cases there are adsorption phenomena in which the molecules are arranged in a particular direcgo tion according to the investigations of Langmuir. Accordingly the property oi! cotton that it can be dyed with direct colours, is not affected by the new process, provided that suitable wetting-out agents are added during the dyeing operationto secure the wetting of the water repellent textiles. In this connection there is a distinction as compared with textile materials which have been immunized by actual practical esteriflcation according to the'processes commonly used in preparative chemistry. While the above example refers to the employment of an anhydride of stearic acid, it is found that anhydrides of other high molecular fatty acids, suchlas palmitic acid, and even oieic acid, may be used with like success.

It is obvious that the invention is not limited.

otherwise to the exact materials or proportions employed, but may be modified in other ways within the scope of the appended claims.

I claim:

1. A process of rendering textiles repellent to water, which includes the steps of treating the same with an emulsion of an anhydride of high molecular fatty acid in an aqueous solution of a stable soap, and heating for substantially 15 to minutes to a temperature of substantially to 150 degrees C., the said soap being characterized in stability by its resistance to decomposition at the temperature of heating.

2. A process 01 rendering textiles repellent to water, which includes the steps of treating the same with an emulsion of an anhydride of a high molecular fatty acid in an aqueous solution of an alkali metal soap, and heating for substantially 15 to 60 minutes to a temperature of 70 to 150 degrees C., the said soap being characterized in stability by its resistance to decomposition at the temperature of heating.

3. A process of rendering textiles repellent to water, which comprises 'steeping the same in an emulsion of an anhydride of a high molecular fatty acid in a solution of a stable soap, drying, and heating for 15 to 60 'minutes to a temperature of substantially 70 to degrees C., the said soap being characterized in stability by its resistance to decomposition at the temperature oi heating.

4. A process of rendering cotton textile goods repellent to water, said goods being unbleached and not having been kler-boiled, which com,- prises' steeping the same in an emulsion containing an anhydride of a high molecular fatty acid. and an alkali metal soap, and exposing for 15 to 30 minutes to a temperature of about degrees C., the said soap being characterized in stability by its resistance to decomposition at the temperature of heating.

ALEXANDER NATIjIANSOI-IN. 

